What is the chemical name of plaster of Paris?
Answer and explanation
Correct answer: Calcium sulphate hemihydrate
The governing concept is the formation and hydration of a salt. Plaster of Paris is calcium sulphate hemihydrate, CaSO₄·½H₂O, obtained by carefully heating gypsum. When water is added, it changes back into gypsum, CaSO₄·2H₂O, and hardens into a solid mass. Therefore option A is correct. Sodium chloride is common salt, sodium carbonate decahydrate is washing soda, and calcium carbonate is a different calcium salt.
Frequently asked questions
What is the correct answer to this question?
Calcium sulphate hemihydrate
Why is this the correct answer?
The governing concept is the formation and hydration of a salt. Plaster of Paris is calcium sulphate hemihydrate, CaSO₄·½H₂O, obtained by carefully heating gypsum. When water is added, it changes back into gypsum, CaSO₄·2H₂O, and hardens into a solid mass. Therefore option A is correct. Sodium chloride is common salt, sodium carbonate decahydrate is washing soda, and calcium carbonate is a different calcium salt.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Acids, Bases, and Salts.
